Process of dyeing.



UNrrn STATES EMIL HAUSSMANN, OF BERLIN, GERMANY, ASSIGNOR TO THE ACTIEN-GESELLSCHAFT FUR ANILIN FABRIKATION, OF SAME PLACE.

PROCESS OF DYEING.

SPECIFICATION forming part of Letters Patent No. 661,985, dated November20, 1900.

Application filed July 10, 1900. Serial No. 23,068. (No specimens.)

T0 (tZZ whom it may concern:

Be it known that I, EMIL HAUSSMANN, of Berlin, in the Kingdom ofPrussia, German Empire, have invented new and useful Improvements inDyeing Processes; and I do hereby declare that the following is a full,clear, and exact description thereof, which will enable others skilledin the art to which it. appertains to make and use the same.

It is well known that colors fast to milling may be produced on W001fiber by the formation of lakes. For this purpose the Woolen goods aremordanted with chromium compounds and subsequently boiled in a solutionof the dyestuff. The characteristical feature of the mordanting processconsists in impregnating the material to be mordant-ed with a boilingsolution of potassium or sodium bichromate with certain assistants,which serve to decompose the bichromate and simultaneously to reduce thechromic acid thus formed. Suitable additions are tartar, oxalic acid,lactic acid, or lignorosin, in combination with sulfuric acid. Sulfuricacid alone or hero-sulfuric acid or certain other additions sometimesemployed set free the chromic acid without reducing it. Hence thereduction can only take place by afiecting the wool fiber. I have nowmade the unexpected discoverythatbysubstitutingfortheabove-mentionedassistants neutral ammonium saltsfor instance, ammonium-sulfateamordanting-bath of most valuable properties is obtained.

The new mordanting-bath which I propose, prepared from potassiumbichromate and ammonium-sulfate, is neutral in the beginning, butbecomes slowly acid on boiling, a part of the ammonium-sulfatedecomposing and ammonia being given off. The latter escapes or reducesthe small quantities of chromic acid, which at the same time have beenset free. Further nitrogen, water, and lower oxides of chromium areformed, which latter immediately become fixed upon the wool fiber. It isevident that in the way described the mordant is but slowly, andtherefore most evenly, deposited on the fiber. Moreover, if a sufficientquantity of ammo- 11in m-sulfate is added the bath may be almostcompletely exhausted.

My new method permits the addition of a number of mordantcoloring-matters directly to the mordanting-bat-h Without the formationof a lake occurring in the bath immediately. As the bath is neutral inthe beginning, the coloring-matter only is at first absorbed by thewool. On boiling the trace ofchromic acid liberated isimmediatelytakenup by the fiber, which possesses a very great affinity for it andcombines with the coloring-matter upon the fiber. The reaction continuesin the same manner and is assisted by the dye-bath becoming more andmore acid until both the coloring-matter and the chromic acid areWithdrawn from the bath and united upon the wool.

My new mordanting process is to be regarded as a technical advantage ofgreat importance for the following reasons:

First. The process is carried out in one single operation, the goodsbeing brought into the boiling-bath, and no subsequent addition of anyingredients whatsoever is required.

Second. The bath is completely exhausted, so that several consecutivedyeing operations may be carried out in the same bath. Mere traces ofchromium that may have been retained can be removed, if necessary, bythe addition of a small quantity of lactic acid.

Third. In many cases direct shades are obtained, which in the dyeingprocesses hitherto employed were only obtained by a subsequent treatmentwith potassium bichromate. Consequently the dyer has it in his power tomatch directly.

Fourth. Since dyestuffs, as arule, dye very evenly in a neutral bath,thedyeings obtained with the help of my mordanting process aredistinguished by their extraordinarily even shades as compared withthose produced upon a chrome-mordant. Whereas in the latter case thecolor-lake is immediately formed jected to my new dyeing process yieldshades which are essentially richer and much faster to milling thanthose produced by the processes hitherto employed.

Sixth. The preparation of the dyebath may be essentially facilitated bykeeping standard solutions containing the dyestufif and all thenecessary ingredients in the proportions required. Such standardsolutions could be prepared by the color-manufacturers and brought uponthe market.

To further illustrate my invention, I give the following directions:

I. DISSOIXB in boiling water one pound of potassium bichromate, onepound of ammonium-sulfate, and one pound of anthracenered in a vat oftwo hundred gallons. Enter with one hundred pounds of slubbing andconnect with a pump. Work for two hours until the bath is exhausted.Rinse and dry.

II. Dissolve in boiling water one pound of chrome fast yellow B, onepound of potassium-bichromate, and one pound of ammonium-sulfate in avat of three hundred gallons. Enter with fifty pounds of worsted yarn ata moderate temperature,lift six times, and raise the temperature slowlyto the boil and dye, gently boiling until the bath is exhausted.

III. Dissolve in boiling water 7.5 pounds of the azo-dyestuff pasteobtained from diazotized picramic acid and meta-toluylene-dia mine,(respectively equivalent proportions of the dyestuffs obtained fromdiazotized picramic acid and chloro -phenylenediamine, Cl:NH :NH :l:2: 4or 1:3: 5,) 1.5 poundsof potassiumbichromate, and 1.5 pounds ofammonium-sulfate in a piece-vat of two hundred gallons, enter withseventy-five pounds of worsted goods at a moderate temperature, and workfor fifteen minutes. Raise the temperature slowly to the boil and dye,boiling until the bath is exhausted.

Having now described my invention and in what manner the same is to beperformed, what I claim as new is- The process for fixingcoloring-matter on wool, said process consisting of simultaneouslymordant-ing and dyeing woolen goods in a bath containing the dyetogether with chromates and neutral ammonium salts.

In witness whereof I have hereunto signed my name, this 23d day of June,1900, in the presence of two subscribing witnesses.

EMIL HAUSSMANN.

Witnesses:

HENRY HASPER, WOLDEMAR HAUPT.

